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N NeedATrade
Trade 6 of 33Updated June 2026

A research dossier · 260 trade-region files across 8 states & territories · AS 1684 + BCA Volume 2 referenced

Hiring a Decking Builder
is half framing, half plumbing.

The boards are what you see. The frame underneath + the junction with your house are what decide whether the deck is solid in 15 years and whether water gets into your wall cavity. The cheap decker undersizes joists, skips flashing where the deck meets the house, and ignores drainage falls. Five years later the boards cup, the joists rot, and the wall cavity grows mould.

450mm

Standard joist spacing for residential decking.

1m

Height above ground = mandatory balustrade under BCA.

15 yrs

Lifespan of a properly built hardwood deck. 3 yrs if not.

In a hurry? Start here

I've got quotes

Compare them properly

Most decking builder quotes price different scopes. See what a real quote contains, line by line.

I need someone now

Handle it urgently

Make-safe price first, full quote second — and verify the licence before anyone starts.

Is this one legit?

Verify this tradie

The free 60-second routine: licence, insurance, ABN, history — before you pay a deposit.

My state

Check your state rules

Licensing, deposit caps and the common gotcha for your state and territory.

Or grab the four printable buyer checklists →

90-second briefing

Read this first

Before you hire a decking builder, know this.

  1. 1

    Timber vs composite is the first decision — it changes price, maintenance and lifespan, not just looks.

  2. 2

    The substructure (bearers, joists, footings) is the real job — confirm spans and footing detail.

  3. 3

    Decks above a height threshold need a permit and compliant balustrade — confirm who handles it.

  4. 4

    Get the board product, fixing system and finish specified in writing.

  5. 5

    Get the licence and insurance details and a written scope before any deposit.

How this page was built

A research dossier, not a referral page.

Sources

Reddit + Whirlpool, ProductReview, AS 1684 (Residential Timber-framed Construction), BCA Volume 2, manufacturer (Trex / Modwood / EkoDeck / NewTechWood) install specs.

Verification

Pricing cross-checked across NSW, QLD, VIC. Joist span tables verified against AS 1684. Balustrade height rules per BCA.

Funding

No decking builder pays for placement. No referral fees. Funded by the supply-side flyer service at tradies.needatrade.com.au/flyers/.

Before we start

The boards are decoration.
The frame + the flashing are the job.

A deck is two trades stacked: structural carpentry below + finish carpentry above. The structural piece (footings, posts, bearers, joists, ledger + flashing) decides whether the deck lasts. The finish piece (boards, balustrade, screws) decides what it looks like at handover. The cheap quote saves on the bit you can't see.

The 10 questions below force the frame, the flashing, and the falls into the open. A working decking builder welcomes them — those are the lines they take pride in. A cowboy stalls — the cheap quote depends on you not asking.

Water + timber. The whole job is about controlling where the first one goes around the second one.

01

How much should it really cost?

Decking is priced per m² + the structural under-frame. Boards are the smaller line — joists + posts + balustrade + flashing carry the real cost.

Six lines a real decking quote shows

  • 1Footings. Concrete footing pads. Depth + size + reo. Soil-class dependent.
  • 2Structural frame. Posts + bearers + joists. Sized to AS 1684. Material + treatment grade.
  • 3Ledger + flashing. Where it attaches to the house. Metal flashing pushed behind cladding. Critical.
  • 4Boards. Species (hardwood / treated pine / composite brand). Fixings (top-screwed / hidden clip / face-screwed). Falls cut into joists.
  • 5Balustrade. If over 1m above ground = BCA-mandatory. Glass / wire / timber / aluminium.
  • 6Finish. Oil / stain (timber) or no finish (composite). First coat before handover.

Indicative ranges · per m²

AU 2026

Treated pine (low-set · standard)$280 – $420/m²
Merbau / Spotted gum hardwood$380 – $600/m²
Composite (Trex / Modwood / EkoDeck)$420 – $700/m²
Balustrade (stainless wire balustrade · per m)$280 – $480/m
Balustrade (glass · per m)$450 – $780/m
Cheap quote (undersized frame · no flashing)under $220/m²
Indicative. Elevated decks (over 1.5m), engineering certificate jobs, heritage match, BAL-zoned material substitution = upper end.

Ask this, exactly

Save · share · screenshot

"Can you send the quote with footing spec, joist + bearer sizes (AS 1684), ledger flashing detail, board species + fixings, and balustrade compliance — line by line?"

02

How to tell a real one from a cowboy.

The decking villain looks identical at handover. The frame is hidden. The flashing is invisible. The damage shows in year five when the deck cups + the wall cavity grows mould.

Red flags — in order of how often you'll meet them

  • !

    No ledger flashing in the quote

    The metal flashing behind the ledger board (where the deck attaches to the house) is the single most-skipped element. Without it: water tracks into the wall cavity. Wall plate rot in 3–5 years.

  • !

    Joist spacing > 450mm

    Standard residential = 450mm centres. Some board manufacturers spec tighter (composite often 350mm). Wider = bouncy deck + premature board failure.

  • !

    No falls cut into the joists

    Boards need to shed water. 1:80 fall away from the house cut into the top of the joists. High-risk operators lay flat → water pools → rot.

  • !

    No balustrade where BCA requires it

    Over 1m above ground = balustrade mandatory. 865mm minimum height. 125mm max gap. Quote-trap operators build to "how it looks" not the code.

  • !

    Wrong fixings (galv on hardwood)

    Hardwood boards need stainless screws (304 minimum, 316 coastal). Galv screws stain hardwood permanently. Composite boards need their hidden-clip system — top-screwing voids the warranty.

The verification routine — 10 minutes, free

  1. ✓
    State licence above threshold. Often a builder's licence (decks are structural).
  2. ✓
    ABN on abr.business.gov.au. Public liability + workers comp.
  3. ✓
    Manufacturer authorised installer for composite brands. Worth real money — keeps the manufacturer warranty alive.
  4. ✓
    Two reference jobs at year 5+. Drive past one. Deck still flat + flashing still hidden behind cladding = built right.
  5. ✓
    Council approval if elevated. Decks over 1m / over 10m² floor area often need CDC or DA depending on council.

Ask this, exactly

"Can you confirm the ledger flashing detail in writing, the joist spacing + fall cut, the balustrade compliance, and the fixings (stainless or hidden clip)?"

03

When does decking need council approval?

Decking — licensing & compliance by state

Choose your state:
NSW $5,000

Regulator

Building Commission NSW

Common gotcha

Written scope; building approval where structural

VIC $10,000

Regulator

Building and Plumbing Commission (BPC, formerly VBA)

Common gotcha

Written scope; building approval where structural

QLD Licensed

Regulator

QBCC

Common gotcha

Written scope; building approval where structural

WA Licensed

Regulator

Building Services Board (Building and Energy)

Common gotcha

Written scope; building approval where structural

SA Licensed

Regulator

Consumer and Business Services (CBS)

Common gotcha

Written scope; building approval where structural

ACT Licensed

Regulator

Construction Occupations Registrar (Access Canberra)

Common gotcha

Written scope; building approval where structural

NT Licensed

Regulator

Building Practitioners Board

Common gotcha

Written scope; building approval where structural

TAS Licensed

Regulator

CBOS (Consumer, Building and Occupational Services)

Common gotcha

Written scope; building approval where structural

Half-time

Frame + flashing + falls. Skip any one, the deck doesn't last.

Quote anatomy, the cowboy test, council approval. The first three sort the working decking builders from the cheap operators who skip the bits you can't see. The next seven are how working builders tell themselves apart — and how the deck still feels solid in 2046.

04

When can they fit you in?

Decking builders 6–12 weeks out for standalone jobs. Spring + early summer = peak. Council approval (when needed) adds 4–8 weeks upfront. Composite material lead times occasionally stretch in peak season.

Approval window.

4–8 weeks if council approval needed. Add to install lead time.

Build duration.

20–30m² deck: 5–8 days. Larger / elevated: 2–3 weeks. Composite is faster than hardwood at install.

Weather + season.

Concrete footings need cure window. Wet conditions delay timber install. Composite less sensitive.

Ask this, exactly

"What's your real start window after approvals + the cure regime for the footings?"

05

What happens next, step by step.

  1. 1Step

    Site visit + design

    Levels, soil, attachment to house. Engineering input if elevated.

  2. 2Step

    Approval (if needed)

    CDC / DA / building permit lodged. 4–8 weeks. Composite manufacturer specs verified.

  3. 3Step

    Footings

    Concrete footing pads dug + poured. 7-day cure before frame work.

  4. 4Step

    Structural frame

    Posts erected. Bearers + joists installed. Ledger fixed to house with flashing behind. Falls cut.

  5. 5Step

    Boards + balustrade

    Boards laid with correct fixings + spacing. Balustrade installed where required. Stair installed if needed.

  6. 6Step

    Sign-off + finish coat

    First oil / stain coat (hardwood). Photos. Defects walk-through. Maintenance schedule handed over.

06

Hardwood, treated pine, or composite?

Option A · most popular

Hardwood

Merbau, spotted gum, blackbutt. Beautiful grain. Needs oil every 1–2 years. 15+ year lifespan when maintained.

Right when: premium natural look + you'll maintain it.

Wrong when: low maintenance is critical.

$380 – $600/m²

Option B

Treated pine

H3 / H4 treatment. Affordable. Cup + shrink more than hardwood. 10–15 years with regular staining.

Right when: budget-led, low-traffic, will paint or stain.

Wrong when: heavy use, high foot traffic, want natural timber look.

$280 – $420/m²

Option C

Composite (Trex etc)

Wood-plastic composite. Zero maintenance. 25-year manufacturer warranty typical. UV fade in first year then stable.

Right when: no maintenance, pool surround, rental property.

Wrong when: heritage area requires real timber, very hot climates (composite gets hot in summer sun).

$420 – $700/m²

07

Warranty — workmanship vs board.

  1. Layer 01

    Statutory structural

    6 years (NSW · VIC) / 6.5 years (QLD) on structural framing + ledger + footings.

  2. Layer 02

    Builder's workmanship

    Typically 12 months to 5 years on the build itself.

  3. Layer 03

    Board manufacturer

    Composite: 25 years typical (Trex / Modwood / EkoDeck). Hardwood: nature-warranted (no manufacturer cover).

  4. Layer 04

    Insurance-backed

    HBC / HW / DBI above state thresholds.

Ask this, exactly

"Could you list workmanship + composite manufacturer warranties (if applicable) + the maintenance regime needed to keep them alive?"

08

Height, attachment, neighbour.

  • Over 1m above ground

    BCA-mandatory balustrade. Council approval often required. Engineering input for elevated decks.

  • House attachment

    Ledger fixed through cladding into structural framing. Flashing pushed behind cladding. Termite-shield required in QLD.

  • Boundary setback

    Most councils require deck 1m from boundary. Some heritage areas tighter.

  • Strata + apartment

    Owners corporation approval. Common-property deck = building manager involvement.

Ask this, exactly

"Do we need council approval given the height + area + setback, and what's the balustrade requirement?"

09

Edge cases — get a second opinion for…

  • Bushfire zone (BAL-rated)

    BAL-12.5+ restricts deck materials. Hardwood species + spacing rules. Some composites approved, others not.

  • Termite-prone areas

    Termite shield mandatory at ledger + post bases (QLD especially). Steel posts often preferred over timber.

  • Pool surround

    Within 1.2m of pool fence: anything climbable (lattice, planter, BBQ) is non-compliant. Specialist pool-deck builder may be needed.

  • Heritage area

    Material match. Often timber-only. Decking visible from street may need council heritage approval.

  • Strata / multi-unit

    Common-property issues. OC approval. Balcony decks have specific membrane requirements over occupied space below.

  • Elevated decks (over 1.5m)

    Engineering certificate typically required. Posts + footings sized for wind + live load. Building permit usually needed.

  • Roof / balcony retrofit

    Existing waterproofing membrane must not be compromised. Specialist installer required.

  • Sloped / stepped ground

    Multi-level deck design. Stepped footings. Engineered design.

  • Composite material substitution

    Some installers swap brands mid-job. Manufacturer warranty void if not installed per brand spec. Confirm brand on the day.

10

After they leave.

Decking aftercare splits by material. Hardwood: oil every 1–2 years. Treated pine: stain every 2–3 years. Composite: rinse occasionally + that's it. The structural frame underneath needs no maintenance — if it was built right.

Hardwood oil schedule.

First coat at handover. Re-coat 12 months later. Then every 18–24 months. Skip = grey weathered look + cracking.

Composite registration.

Trex / Modwood / EkoDeck warranties need to be registered with the manufacturer within 30 days. Cheap installer often forgets.

Defects period.

3-month walk-through after first wet season. Cup or warping shows here. Touch-ups + adjustments.

Annual rinse.

All materials: gentle hose-down + occasional deck cleaner. Pressure-washing voids most warranties.

Ask this, exactly

"What's the maintenance schedule for the material I chose, will you register the composite warranty for me, and what's your defects-period walkthrough?"

If you've read this far

A decking builder who shows you the flashing detail before the boards is not a unicorn. It's the bar.

The verification routine below is how you confirm any decking specialist you find — their licence number, insurance certificate, ABN, specialist endorsements, and references — before you sign or pay a deposit. We don't introduce, list or recommend specific tradies. No paid placement.

✓ No referral fees✓ Verified means all 10✓ No spam
Verify any decking specialist's licence 60-second routine · 6 free checks

Editorial position: we don't list, rank or recommend tradies on this site.
The separate operator platform — members.needatrade.com.au — opens later this year.

The toolkit

Use these before you sign.

The four components below apply to every Australian trade contract. The trade-specific sections above add the layer on top.

47 homeowner quotes · Reg State trade regulator + work-safety regulator · AS AS 1684 · 9 operator quotes · Last reviewed June 2026

Quote anatomy

What a real quote should contain

01

Operator + ABN

Full legal name + active 11-digit ABN

Verify on the Australian Business Register before paying any deposit. If the ABN isn't active, the contract has no enforceable counterparty.

02

State trade licence

Licence number + class on the quote

Cross-check on the relevant state regulator (linked in the glossary licence-check section). Confirms they can legally do the work.

03

Public liability insurance

$10–20 million cover, still current (not expired)

This is what pays if they damage your home — or a neighbour's — or someone is injured during the job. Ask them to email you the insurance certificate; "I'm covered, mate" is not proof.

04

Workers' insurance

In place if they bring any workers onto your property

If a worker is hurt on your property and the operator has no workers' insurance, you can be the one left liable. A genuine sole trader with no employees may not need it — just ask.

05

Itemised scope of work

What's included, what's not, line by line

"Standard installation" means nothing in court. Specific scope items are what get enforced.

06

Materials specification

Brand, grade, quantity, AS standard where applicable

Prevents the "we used what was on the truck" substitution that turns up under failure inspections.

07

Variations clause

How changes get priced + agreed, in writing

No written variation = unenforceable. Verbal "we'll work it out" is how budgets blow out by 40%.

08

Deposit + progress

Within your state's legal cap (e.g. NSW 10%; VIC 10%/5% by threshold; QLD tiered 20%/10%/5% by job value)

Above-cap deposits are illegal. Caps differ by state — check your state's current regulator guidance. Progress payments should align with completed stages, not arbitrary dates.

09

Warranty terms

Workmanship period + manufacturer warranty pass-through

Statutory warranty applies regardless, but written terms accelerate enforcement.

10

Completion definition

What "practical completion" means for this job

Triggers final payment + starts the defects liability period.

11

Dispute path

Named regulator/tribunal for disputes (e.g. NCAT, VCAT, QCAT)

Knowing the path before signing makes you a less attractive target for a dispute.

If a quote you receive is missing any of these, ask for them before you sign or pay a deposit.

The working operator vs the cowboy

Where
✓ Working operator
✗ Cowboy

Quote

Written, itemised, with named scope + exclusions. Numbered + dated.

A number on a text. "I'll do it for $X."

Licence

Licence number on the quote; matches the name on the state register.

"I'll send the licence later." Never does.

Insurance

Emails you the insurance certificate the same day you ask.

"I'm insured, mate." Never actually sends the certificate.

Deposit

Within statutory limit. Held in their account, receipted.

Asks for cash up front. Above the legal limit.

Variations

Written. Cost + time impact. You sign before work changes.

Verbal "we'll sort it out". Surprise invoice at the end.

Warranty

Written workmanship period. Manufacturer cert handed over.

"My word's my warranty." No paper.

References

Three recent jobs with photos + contact for past clients.

"All my reviews are on Google."

Clean-up

Final clean defined in scope. Photos taken at handover.

Site left messy. Promises to "come back tomorrow".

Ask this, exactly

Could you send your state trade licence number, current Certificate of Currency for public liability, and ABN before I confirm — and please put the itemised scope, deposit terms, and variation clause in writing too?

Send via SMS or email before booking. A working operator replies the same day with all of it attached. A cowboy stalls.

Deposit checklist

Before you pay a decking builder deposit, collect these

  • Licence number

    State trade licence + class, printed on the quote. Verified on the regulator register.

  • ABN

    Active 11-digit ABN, entity name matching the licence. Checked on abr.business.gov.au.

  • Certificate of currency

    Current public-liability certificate (and workers comp if they bring workers). The insurer’s one-page proof — not “I’m covered, mate”.

  • Written, itemised quote

    On letterhead, numbered and dated. Not a number in a text message.

  • Scope inclusions / exclusions

    What’s in, what’s out, line by line. “Standard installation” is not a scope.

  • Deposit amount

    Within your state’s statutory cap (NSW 10%; QLD tiered 20% / 10% / 5% by job value; VIC 10% / 5% by threshold; other states vary). Check your regulator before paying.

  • Variation clause

    How changes get priced and agreed — in writing, before the work changes.

  • Warranty terms

    Workmanship period + manufacturer pass-through, with year limits and what triggers a callback.

  • Compliance / handover paperwork

    The certificate or compliance document you’ll receive at completion (varies by trade and state).

  • Defects / callback process

    The defects-liability period and how you call them back for an obvious fault — in writing.

  • Board product and fixing system specified

    Decking builder-specific

  • Building permit / balustrade compliance (raised decks)

    Decking builder-specific
Collect every item before you transfer a deposit. If a tradie stalls on any of them, that is the answer.

Related references

Briefing

The 12 questions →

 Operational

Verify a tradie →

 Translation

Glossary →

 Provenance

Source ledger →
← Back to all 33 trades

Trade 6 of 33.

Standards

Standards often relevant to this trade

These are orientation references only — not a complete or job-specific list. Ask the licensed contractor to confirm the current standards, the NCC, and any state or territory requirements that apply to your job.

Plain-English definitions, who’s responsible, and an “ask this” for each → see the glossary.